Mammalian sarcoma viruses are powerful systems to understand the molecular basis of cell transformation. Our goals are: 1. to identify "sarcoproteins" coded by putative src genes of three classes of mammalian sarcoma viruses, Moloney murine sarcoma virus (M-MSV(MLV)), Harvey and Kirsten sarcoma viruses (Ha-SV(MLV), Ki-SV(MLV)), and woolly sarcoma virus (WoSV(WoLV)), and 2. identify cell coded transformation-associated polypeptides that may be induced or modified, and which contribute to the transformed cell phenotype. To obtain highly parallel untransformed and transformed cell lines, two permanent cell lines are being transformed by M-MSV, Ha-SV, Ki-SV, and WoSV. Transformed cell-specific polypeptides are identified by high resolution 2D isolelectric focusing-SDS polyacrylamide gel electrophoretic analysis of transformed and untransformed parental lines. Ten electropherograms are run simultaneously and are analyzed and quantitated by computer scanning. Cell fractionation will be employed to identify polypeptides associated with specific cell organelles. Attempts will be made to raise antibodies against viral coded sarcoproteins by producing tumors in young rabbits by inoculation with sarcoma viruses and inoculating syngeneic animals with extracts of transformed cells. These antisera will be used as probes to identify sarcoproteins by highly sensitive immunoautoradiographic procedures using gels and/or permanent, reusable polypeptide paper imprints of 2D electropherograms together with 125I-labeled second antibody or Staphylococcus A protein. By the same technology, antibodies to virion polypeptides will be used to search for possible recombinant proteins that are partly viral and partly cell coded, and 125I-labeled lectins will be used to quantitate transformed cell-associated modifications in glycopolypeptides. To prove viral coding, peptide maps of sarcoma virus RNA in vitro translation products will be compared to those of virion polypeptides and of transformed cell-associated polypeptides from 2D gels. As long range goals, transformation defective temperature sensitive mutants may be isolated, transformed cell revertants examined, and transformation-associated polypeptides purified and further analyzed.